This invention relates to sorting, i.e. classifying, of blueberries to separate ripe berries from unripened berries.
It is known that ripe blueberries have a specific gravity greater than that of water and that unripe berries have a specific gravity less than that of water. A common practice when harvesting blueberries is to pour the ripe and unripe mixture of blueberries into a tank of water to not only wash them, but also cause ripe berries to sink and green or unripened berries to float on the surface to be skimmed off and separated. A difficulty experienced is that some of the ripe berries do not readily sink but rather remain floating to be skimmed off and discarded with the unripened fruit, resulting in losses. Using this practice, the tank also tends to become filled with berries, a condition which prohibits effective classification. And basically, the process is only partially effective unless performed very slowly and with relatively small batches of berries. Even then, there is little control over those berries not fully ripe but not really green. Such berries are typically sour but flavorful and highly valuable for use in pies or the like. It would be desirable to be able to controllably separate fully ripe berries from those not fully ripe, and to further separate green berries and stems.